If you are restricting your body may be demanding the minimal in order to ward of starvation. It reminds me of dehydrated cattle on a long dry march stampeding to a river. A lot of them will die in that stampede. The survival imperative at such an extreme state of vulnerability takes over. I wonder, if you fed yourself well every day for one month, would that sugar craving fall by the wayside? You ask, "How do I pass by these substances?" Well, how does a dehydrated herd of cattle pass by the river? The answer to both questions is the same.